Addition of clonidine,Magnesium, and Ketamine for Intravenous Regional Anesthesia

The aim of the work is to compare the effect of adding each of clonidine, ketamine, and magnesium sulphate, to the relatively small doses of lidocaine on the characters of the produced IVRA for upper limb surgical procedures, to find out the best improving adjuvant without or at least with minimal side effects.